"Hot weather favors violence, both because it increases bodily discomfort and irritability, and because it brings people out of doors where contact and conflict can occur. Add the idleness of a Sunday afternoon, and the stage is well set. Disastrous riots do, in fact, seem to start most frequently on Sunday afternoon in hot weather. The peak of lynchings is in the summer months."Het prentje: via signs and wonders.
Gordon W. Allport, The Nature of Prejudice, Anchor Books, New York, 1954.